Battery EIS Resistance-Rate Analysis for Electrode Arc Identification
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Solution Overview
Problem
Existing battery management systems struggle to distinguish between arcs in electrochemical impedance spectroscopy (EIS) profiles that are associated with increases in negative electrode resistance and positive electrode resistance, making it difficult to diagnose electrode degradation accurately.
Innovation Solution
A battery management apparatus and method that uses an EIS instrument to generate profiles, calculates arc resistance values, and determines whether each arc is negative electrode-originated or positive electrode-originated based on resistance change rates and preset thresholds, allowing for specific diagnosis of electrode degradation states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional EIS measurement is used to estimate battery state, then battery state can be monitored, but the ability to distinguish between negative electrode and positive electrode degradation is insufficient
Solution Approach 1:
The patent segments the EIS arcs into negative electrode-originated arcs and positive electrode-originated arcs by analyzing resistance change rates at different SOC sections. This segmentation allows independent diagnosis of each electrode's degradation state, resolving the inability to distinguish arc origins in conventional EIS measurements.
Solution Approach 2:
The patent changes the parameter being measured from static arc resistance to dynamic resistance change rate (dR/dSOC). By measuring how resistance changes with SOC rather than just the absolute resistance value, the system can identify which electrode each arc corresponds to, improving measurement precision for electrode-specific degradation.
2Reliability
If multiple arcs in EIS profile are analyzed together, then overall battery resistance is captured, but the specific contribution of each electrode cannot be determined
Solution Approach 1:
The patent performs preliminary classification of arcs into negative electrode-originated and positive electrode-originated groups before conducting degradation analysis. By pre-segmenting the arcs based on resistance change rate characteristics at different SOC sections, the system simplifies subsequent analysis and improves reliability without requiring complex real-time differentiation.
3Measurement precision
If resistance change rate threshold is set to distinguish electrode arcs, then arc origin identification becomes possible, but the method requires additional processing complexity
Solution Approach 1:
The patent uses the battery's own operational data (voltage, current, SOC) to calculate resistance change rates and automatically identify arc origins without requiring external intervention or complex additional sensors. The system serves itself by utilizing existing measurement data to perform the differentiation, reducing overall system complexity while maintaining high detection precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables precise differentiation and diagnosis of negative and positive electrode degradation states, improving the accuracy of battery state diagnosis through EIS profiles.
Implementation Method 1
an electrochemical impedance spectroscopy (EIS) instrument configured to output an alternating current (AC current) to a battery at a plurality of times and generate a plurality of EIS profiles, each EIS profile representing a resistance of the battery
Data Source
AI summary
A battery management apparatus includes an EIS unit configured to output an AC current to a battery at a plurality of times and generate an EIS profile representing a resistance of the battery as a corresponding relationship between a real part and an imaginary part at each of the plurality of times, and a control unit configured to obtain the plurality of EIS profiles for the battery generated by the EIS unit, determine a plurality of arcs in each of the plurality of EIS profiles, calculate an arc resistance value for each of the plurality of determined arcs, calculate a resistance change rate for the arc resistance value between corresponding arcs among the plurality of arcs, and determine each of the plurality of arcs as a negative electrode-originated arc or a positive electrode-originated arc based on the plurality of calculated resistance change rates and a preset criterion change rate.